Voltage measurement probes couple an electrical signal from a device under test (DUT) to a test and measurement instrument, such as an oscilloscope and the like. Measurement probes include a probe head, a transmission line, such as a coaxial cable, and a connector housing having a signal connector, such as a BNC, SMA, BMA connector and the like, which connects to a mating signal connector on the measurement instrument. The probe head generally includes a metal tube or housing having a substrate disposed therein. A probing tip (or socket) is disposed in a holder that is inserted into one end of the probe head. The probe tip or socket extends from the holder and is electrically coupled to the substrate. The substrate has passive or active circuitry formed thereon that provides high impedance to the circuit generating the signal under test. The substrate circuitry is electrically coupled to the transmission line. The other end of the transmission line is electrically coupled to the signal connector.
The electrical connection between the substrate and the probe tip (or socket) is facilitated by a contact that extends over an end of the substrate. Conventional probe tip contacts are typically formed from electrically conductive materials such as gold foil, ribbon, or an electrically conductive elastomer. While conventional contacts have generally proven to be effective means of establishing electrical connections, such contacts are frequently prone to mechanical wear, misalignment, breakage and punch-through, typically resulting in degradation of the contact and outright failure or loss of the electrical connection. Thus, the reliability of conventional probe tip contacts over time is compromised.
Furthermore, conventional probe tips are typically permanently fixed to the contacts (e.g., by soldering) to maintain a reliable electrical connection. This makes removal of probe tips (e.g., for replacement) difficult and costly.
Thus, there is a need in the art for a probe tip contact that is capable of establishing a flexible, yet reliable long-term electrical coupling between a substrate and a probe tip.